Saint-Genis-Pouilly is composed of two market towns (Saint-Genis and Pouilly) and two hamlets (
Pregnin and Flies). The two market towns have both continued to expand and now practically merge into one, however the two hamlets still remain separate from each other and from the two towns. The elevation of the commune varies from 419 m (at the extreme south of the commune, to the confluence of the rivers Allondon and Nant de l'Ecra) to 502 m (at the extreme north of the commune, in the village of Flies). The commune is situated at the limit between the plains surrounding Geneva and the first foothills of the Jura. As indicated on the map opposite, the communes surrounding Saint-Genis-Pouilly are:
Thoiry,
Sergy,
Crozet,
Chevry,
Prévessin-Moëns and
Satigny (Swiss).
Hydrology Many water courses traverse or border Saint-Genis-Pouilly: Lion,
Allondon, Nant de l'Ecra, Bief de la Janvoin, Ouaf, Grand Journans and Petit Journans. In 2005 and 2006, these water courses were subject to a ban on water extraction as a result of the drought. In 2004, only the Allondon and the Lion would have been restricted. The depth of the Allondon is measured at Saint-Genis-Pouilly by a network HYDRO station which transmits these readings by telephone.
Climate The meteorological station situated at Geneva International Airport, Cointrin, furnishes measurements of the weather relevant to Saint-Genis-Pouilly. This station is situated only km from the centre of the commune and at a similar elevation ( m). Data from this station is available in real time from MétéoSuisse. Saint-Genis-Pouilly, like the whole of the Pays de Gex and the Canton of Geneva, knows the touch of the
Joran, the cold wind which descends towards
Lac Léman from the high Jura, where it sometimes provokes a storm.
Natural risks According to a study made in 2002, commissioned by the Department of Agriculture and the Forests of Ain, Saint-Genis-Pouilly is classed in a zone at risk from flooding. According to another official publication, the commune is classed in a zone at risk from torrential downpours and rapid flooding. However, according to the list of major risks to Saint-Genis-Pouilly published on the portal of the website of the Ministry of Ecology, "Prevention of major risks", the commune is classed in a zone at risk from overcrowding from man's activities. These three different qualifications of risk cannot be explained. Along with the other communes in the canton of Gex, Saint-Genis-Pouilly is classed in seismic zone Ib, which is to say that the seismic risk is low. A new classification is being prepared by the Ministry of Ecology, but it does not seem that this will significantly change the classification of the communes in the Pays de Gex.
Nature zones That part of the Allondon valley which is found within the territory of the commune constitutes a natural zone with interesting ecology, fauna and flora (
ZNIEFF type I). ; The commune is sparsely wooded: the area occupied by forests is 7%. ==History==